We experimentally studied the influence of dopant atoms and surface oxide stress on the physical properties of two-dimensional Si (2D-Si) using UV-Raman spectroscopy and a photoluminescence (PL) method. The PL method showed that the bandgap EG of n+/p+ 2D-Si strongly depends on the impurity dopant density N , which is caused by the EGnarrowing effects. However, the N dependence of EG of n+ 2D-Si is about one third of that of n+ 3D-Si, which is probably attributable to the impurity band modulation in 2D-Si. On the other hand, UV-Raman results showed that a tensile strain of 2D-Si, applied by the expansion coefficientdifference between 2D-Si and surface oxide, can be relaxed by decreasing the surface oxide thickness TOX . As a result, EG of 2D-Si rapidly increases with decreasing TOX. This strain dependence of EG of 2D-Si is much larger than that of 3D-Si, which is not physically understood at present.原著 2014 年度神奈川大学総合理学研究所共同研究助成論文